Can Trees Sound the Alarm?
Scientists say trees may be able to warn us when a volcano is about to erupt.
Alessandra Baltodano/Chapman University
Dr. Alexandria Pivovaroff of Occidental College gathers data about trees that have been exposed to extra carbon dioxide from a nearby volcano.
It’s not easy to tell when a volcano will erupt, and that uncertainty can be dangerous for people who live near volcanoes. But scientists have found something that may help them predict volcanic eruptions. They can study the color of tree leaves.
When a volcano is about to erupt, hot, liquid underground rock called magma moves through Earth’s crust. This movement causes a release of gases, including carbon dioxide, from underground into the air. So the presence of extra carbon dioxide can be a sign that an eruption is about to happen. But until recently, scientists needed to visit volcanoes to measure the amount of carbon dioxide around them—and that can be dangerous. It’s also difficult to visit all the parts of the world where there are active volcanoes.
Here’s where trees come in.
Tree leaves take in carbon dioxide like humans take in oxygen. When a volcano releases carbon dioxide just before it erupts, trees in the area absorb that carbon dioxide. In many cases, the extra carbon dioxide makes the trees’ leaves greener than usual. This means extra-green tree leaves are one sign that a volcano in the area is about to erupt.
Adriane Colbur
Chapman University student Holland Hatch and Universidad Nacional de Costa Rica student José Vargas-Murillo perform tests on leaves that have been exposed to carbon dioxide from a volcano.
Recently, NASA joined forces with a U.S. government research group called the Smithsonian Institution to study the link between carbon dioxide and leaf color. Why NASA? The U.S. space agency says that when leaves change color, it can be seen from space. This means it’s possible to use satellites to observe the extra-green tree leaves that might be a sign that a volcano is about to erupt!
It’s not a perfect way to predict eruptions. For one thing, some volcanoes are in areas with very few trees. Also, some trees don’t respond to more carbon dioxide by getting greener. But scientists say that when it comes to volcano safety, it’s a good idea to have as many tools as possible.
